1. Field of the Invention
This invention relates to an adjusting device for the conveying belt of a planer, particularly to one provided with a rear roller unit composed of two adjusting plates and a rear roller, simple in structure and able to quickly adjust the tightness of the conveying belt of a planer.
2. Description of the Prior Art
A conventional planer is provided with a conveying device 10 on its base 1 for conveying and feeding a work piece, as shown in FIG. 1. The conveying device 10 is composed of a conveying belt 11 for conveying the work piece and an adjusting roller 12 for adjusting the tightness of the conveying belt 11. The adjusting roller 12 has its opposite ends respectively fixed with an adjusting threaded rod 121 and its central portion fixed with a slide rod 122 respectively extending outward vertically. The base 1 of the planer has its opposite ends of one side respectively bored with an adjusting hole 13 for the adjusting threaded rod 121 to be screwed therein and has its central portion bored with a slide hole 14 for receiving the slide rod 122 therein. Thus, the adjusting roller 12 can be slidably assembled on the base 1 and the tightness of the conveying belt 11 can be properly adjusted by adjusting the position of the adjusting threaded rods 121 in the adjusting holes 13.
However, the adjusting roller 12 of the conveying device 10 of the conventional planer must be provided with the adjusting threaded rods 121 and the slide rod 122 in order to enable the adjusting roller 12 to be slidably assembled on the base 1 of the planer, thus complicating the structure and increasing difficulty in assembly. In addition, the base 1 of the planer must be bored with the adjusting holes 13 and the slide hole 14 respectively for receiving the adjusting threaded rods 121 and the slide rod 122 of the adjusting device 10, thus increasing processing cost.